In Japanese, the sound of a dog barking is "wan wan" ( ワンワン). This is also used as the Japanese word for dog.
Many Japanese words are based on sensory perceptions such as sound, feeling, smell, color, shape or movement. These are called ideophones — they exist in almost every language.
In most languages ideophones are rare. In Japanese, they're common. It's considered one of the unique features of the language.
Ideophones are easy to spot in Japanese because they are always doubled up. These are common expressions.
1. Doki Doki (どきどき)The sound your heart makes when it's beating fast; excitement.
2. Zoku Zoku (ぞくぞく)The sensation of a shiver going up your spine; thrill.
3. Dara Dara (だらだら)Water trickling; sluggish.
4. Chiku Chiku （ちくちく）The type of tingling sensation you might on your skin get from a woollen sweater; prickling pain.
5. Bachin Bachin (ばちんばちん)The sound of something slamming down; heavy typing.
6. Iro Iro (色々)The word iro iro can be literally translated "color color". It means various.
7. Bori Bori (ぼりぼり)To eat with a crunching sound.
8. Bera Bera (べらべら)Nonstop talking (chattering); thin and flimsy.
9. Dan Dan (だんだん)Steps; slowly but surely.
10. Gachi Gachi (がちがち)Chattering teeth; frozen; worried; stiff.
11. Neba Neba (ねばねば)Stickiness — natto is neba neba.
12.Baku Baku (ばくばく)The sound of your heart racing; eating quickly.
13.Sui Sui (すいすい)Smoothly (no problems).
14. Sowa Sowa (そわそわ)Fidgety, nervous or restless.
15. Rabu Rabu (ラブラブ)This is Japanese English based on the English word "love". It means romantic.
16. Nya Nya (にゃにゃ)The sound a cat makes (meow); a cat.
17. Shiku Shiku (しくしく)Crying discretely; dull pain.
18. Waza Waza (わざわざ)Doing something on purpose (rather than incidentally). For example, when companies intentionally put engrish on their products to boost sales.
Why Ideophones?Linguists tend to view ideophones as primitive. If a cat says "meow" so you decide the word for cats should be "meow" — it's not exactly the most imaginative choice.
Japanese is obviously a complex, advanced language. The reason it has so many ideophones is tied to Japanese ideas about nature. The Japanese delight in creating words that mimic natural sounds and phenomena.
Usually, ideophones have more formal synonyms. For example, dogs are inu (犬) and cats are neko (猫).
Manga IdeophonesIdeophones are added to Japanese all the time. It's one of the fastest growing aspects of the language. This is largely driven by manga (comics).
Manga tend to invent new ideophones. Sometimes these catch on.